This is the Futaba S9254 Digital Coreless High Torque, High Speed Helicopter Gyro Servo with J Connector. This hyper fast digital servo, ideal for tail rotor control on helicopters as well as many other applications requiring the ultimate in speed of response, yet still having good torque.

This servo features a coreless motor for reduced weight and high-speed response, and digitally enhanced microprocessors that cut in half the response time from transmitter input to servo reaction. A dual ball bearing gear train and a dust and water resistant-not water proof Black plastic case.